B737-300 experiences gear unsafe condition. Recycling of gear clears problem. Subsequent inspection ...

Attributes
ACN	735420
Time
Date	200704
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 2000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : zzz.tower
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	approach : visual
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 100 flight time total : 15000 flight time type : 200
ASRS Report	735420
Events
Anomaly	aircraft equipment problem : critical non adherence : company policies
Independent Detector	aircraft equipment other aircraft equipment : gear unsafe lights other flight crewa
Resolutory Action	flight crew : overcame equipment problem flight crew : landed in emergency condition
Consequence	other
Supplementary
Problem Areas	Flight Crew Human Performance Company Aircraft
Primary Problem	Aircraft

Narrative:

Upon gear extension at ZZZ arrival; left main gear unsafe indicator light remained illuminated with no illumination of associated green gear down and locked indicator light. A missed approach was conducted at approximately 1000 AGL and after the QRH 'manual gear extension checklist' was accomplished with no change of left main gear position indications noted; and the 'gear down locked visual indicator' confirmed the gear not down/locked; an emergency was declared. #2 VHF utilized on ZZZ1 operations frequency to contact dispatch and maintenance controller. The flight attendants were advised to prepare the cabin. Maintenance control concurred with trying one cycle of the gear handle which resulted in normal gear down and locked indication. The visual indicator was 're-sighted' and confirmed the down/locked position. ATC and flight attendants were advised of the resultant gear status and a normal landing was made with emergency vehicles following us to the gate. Landing fuel was 3500 pounds and minimum fuel had been declared prior to final approach. At the gate a nonstandard chock was discovered within the wheel well by ZZZ1 maintenance personnel. The captain (myself) did the walkaround at our departure point with flashlight in hand. I understand that the wheel well area is to be checked for 'general condition; hydraulic leaks; main gear viewer clean and wheel well light on;' in addition; 'close inspection to determine the absence of foreign objects' is also required. Suggestions: I would re-emphasize the need for focused close inspection of the wheel well area during the preflight exterior inspection. I myself will be more closely focused in searching for foreign objects during the wheel well inspection. I would also suggest re-emphasized prohibition on the placing of objects in such areas. Finally; I would suggest that maintenance do an exterior inspection after major maintenance procedures with an associated aircraft logbook entry. This notation would also serve to alert flight crews of the previously conducted major maintenance.

Original NASA ASRS Text

Title: B737-300 EXPERIENCES GEAR UNSAFE CONDITION. RECYCLING OF GEAR CLEARS PROBLEM. SUBSEQUENT INSPECTION DISCOVERS GROUND CHOCK IN GEAR WELL WHICH IMPEDED EXTENSION/RETRACTION MECHANISM.

Narrative: UPON GEAR EXTENSION AT ZZZ ARR; L MAIN GEAR UNSAFE INDICATOR LIGHT REMAINED ILLUMINATED WITH NO ILLUMINATION OF ASSOCIATED GREEN GEAR DOWN AND LOCKED INDICATOR LIGHT. A MISSED APCH WAS CONDUCTED AT APPROX 1000 AGL AND AFTER THE QRH 'MANUAL GEAR EXTENSION CHKLIST' WAS ACCOMPLISHED WITH NO CHANGE OF L MAIN GEAR POS INDICATIONS NOTED; AND THE 'GEAR DOWN LOCKED VISUAL INDICATOR' CONFIRMED THE GEAR NOT DOWN/LOCKED; AN EMER WAS DECLARED. #2 VHF UTILIZED ON ZZZ1 OPS FREQ TO CONTACT DISPATCH AND MAINT CTLR. THE FLT ATTENDANTS WERE ADVISED TO PREPARE THE CABIN. MAINT CTL CONCURRED WITH TRYING ONE CYCLE OF THE GEAR HANDLE WHICH RESULTED IN NORMAL GEAR DOWN AND LOCKED INDICATION. THE VISUAL INDICATOR WAS 'RE-SIGHTED' AND CONFIRMED THE DOWN/LOCKED POS. ATC AND FLT ATTENDANTS WERE ADVISED OF THE RESULTANT GEAR STATUS AND A NORMAL LNDG WAS MADE WITH EMER VEHICLES FOLLOWING US TO THE GATE. LNDG FUEL WAS 3500 LBS AND MINIMUM FUEL HAD BEEN DECLARED PRIOR TO FINAL APCH. AT THE GATE A NONSTANDARD CHOCK WAS DISCOVERED WITHIN THE WHEEL WELL BY ZZZ1 MAINT PERSONNEL. THE CAPT (MYSELF) DID THE WALKAROUND AT OUR DEP POINT WITH FLASHLIGHT IN HAND. I UNDERSTAND THAT THE WHEEL WELL AREA IS TO BE CHKED FOR 'GENERAL CONDITION; HYD LEAKS; MAIN GEAR VIEWER CLEAN AND WHEEL WELL LIGHT ON;' IN ADDITION; 'CLOSE INSPECTION TO DETERMINE THE ABSENCE OF FOREIGN OBJECTS' IS ALSO REQUIRED. SUGGESTIONS: I WOULD RE-EMPHASIZE THE NEED FOR FOCUSED CLOSE INSPECTION OF THE WHEEL WELL AREA DURING THE PREFLT EXTERIOR INSPECTION. I MYSELF WILL BE MORE CLOSELY FOCUSED IN SEARCHING FOR FOREIGN OBJECTS DURING THE WHEEL WELL INSPECTION. I WOULD ALSO SUGGEST RE-EMPHASIZED PROHIBITION ON THE PLACING OF OBJECTS IN SUCH AREAS. FINALLY; I WOULD SUGGEST THAT MAINT DO AN EXTERIOR INSPECTION AFTER MAJOR MAINT PROCS WITH AN ASSOCIATED ACFT LOGBOOK ENTRY. THIS NOTATION WOULD ALSO SERVE TO ALERT FLT CREWS OF THE PREVIOUSLY CONDUCTED MAJOR MAINT.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

B737-300 experiences gear unsafe condition. Recycling of gear clears problem. Subsequent inspection discovers ground chock in gear well which impeded extension/retraction mechanism.